Question: Simplify the following expression: $ y = \dfrac{7z + 5}{9z} + 4 $
Explanation: In order to add expressions, they must have a common denominator. Multiply the second expression by $\dfrac{9z}{9z}$ $ \dfrac{4}{1} \times \dfrac{9z}{9z} = \dfrac{36z}{9z} $ Therefore $ y = \dfrac{7z + 5}{9z} + \dfrac{36z}{9z} $ Now the expressions have the same denominator we can simply add the numerators: $y = \dfrac{7z + 5 + 36z}{9z} $ $y = \dfrac{43z + 5}{9z}$